There is no getting away from it…..winter is here!! With this comes an increased susceptibility to all manner of colds and weird infections. More time indoors, artificial ventilation etc, not to mention reduced sunlight (more on that later), all play their part.

Nutrition isnt going to be an all encompassing guarantee to be free of all bugs all winter long, but it can play a huge role in building your resistance.

Zinc

Zinc is a vital mineral for immunity. Whilst the evidence base for vitamin C affecting the common cold is mixed, the evidence for zinc reducing the duration of a cold is very strong. Zinc is used by our white blood cells to code genes that control the way in which our white blood cells interact with pathogens that they encounter. So essentially it increases their efficacy when faced with an invader. Find zinc in foods such as shellfish, pumpkin seeds, and walnuts.   If using a supplement, do not exceed 15mg a day for women, and 30mg a day for men.

Vitamin C

Ok, so whilst its evidence is not as strong as zinc in terms of treating infections, we know it plays a physiological role in immunity, which makes it important still in my view. Vitamin C is used by white blood cells to instigate the oxidative burst – a burst of free radicals that they release when faced with pathogens of infected cells. These free radicals can destroy the pathogen or cell. Vitamin C also increases white cell motility, assisting better migration to the site of infection. Best food sources are peppers, spinach and raw greens, kiwi fruit, and of course citrus, that has the added benefit of high flavonoid content which can increase absorption.

Vitamin D

I alluded to less sunlight being an issue earlier. Well, that link is all about vitamin D. The primary source of vitamin D for Humans is the conversion of cholesterol into vitamin D precursors when our skin is exposed to ultra violet radiation – ie THE SUN. Even in the summertime us Brits get a pretty bum deal, so in the winter time we dont stand a chance.Vitamin D was once thought to just be vital for skeletal health. how wrong we were. Its roles are vast and ever growing. There are vitamin D receptors on the surfaces of many immune cells, showing that it binds and instigates changes. It reduces inflammatory cytokines, and increases the production of antimicrobial proteins.  When there is no sun (the sun….yeah I heard of that once), then food sources are few and far between. The best are full fat dairy products, eggs, and oily fish. One thing I did think was a stroke of genius is that Marks & Spencers have created a type of mushroom that is vitamin D enriched. Check THESE badboys out:http://www.dailymail.co.uk/news/article-2772980/The-Vitamin-D-mushrooms-M-S-say-eating-just-three-new-range-provide-recommended-daily-amount.html

Otherwise, its going to be a supplement. I personally take 1000 IU/25 mcg daily.

Polysaccharides

these are amazing specialised sugars that exist in certain foods. These arent negative, problematic sugars that should be avoided. Instead, they are sugars that can have almost wondrous effects upon immunity. They have been shown to cause an increase in the production of white blood cells (our immune system’s army), and their response to pathogens or damaged cells. Just a small amount of these compounds daily can really give the immune system a bit of a kick. How do they do this? It appears polysaccharides do this by interacting with peyers patches. These patches are small patches of tissue within the walls of the digestive tract that basically act like a surveillance station. They are densely packed with cells that continually monitor the contents of the gut. When you think about it, the digestive system is a direct interface between the outside world and the inner workings of our body, so a perfect route in for opportunistic pathogens. This is why its contents are so widely monitored. It is believed that mushroom polysaccharides closely resemble polysaccharides that are displayed on the outer surfaces of some pathogens. When these polysaccharides move over the peyers patches, the cell population there think that there is in fact a pathogen present that is responsible for the presence of these polysaccharides. They respond to this by instigating a biochemical cascade, releasing messenger compounds called cytokines that relay this ‘attack’ message to the rest of the immune system. This cytokine cascade encourages an increased production of certain lines of white blood cells – the army of the immune system. The best food sources of these are mushrooms like shiitake, and maitake (if you can find them in the UK), and also goji berries.

CLICK HERE to see my Famous Flu Fighting Soup!

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